Search results for "Matrix"
showing 10 items of 3205 documents
Robust H∞ reliable control for delta operator switched systems with time-varying delays under asynchronous switching
2014
The problem of robust H∞ reliable control for a class of delta operator switched systems with time-varying delays and actuator faults under asynchronous switching is considered in this paper. Asynchronous switching means that the switches between the candidate controllers and system modes are asynchronous. Based on the average dwell time approach and delta operator theory, a state feedback controller is designed such that the closed-loop system is exponentially stable with H∞ performance in the presence of actuator faults. The obtained results are formulated in the form of linear matrix inequalities (LMIs). Finally, a numerical example is provided to demonstrate explicitly the feasibility …
New fault detection filter design approach for continues-time switched systems
2012
This paper investigates the problem of fault detection filter design for continuous-time switched systems. The designed fault detection filter is assumed to be asynchronous with the original systems. Attention is focused on designing a fault detection filter such that the estimation error between the residual and the fault is minimized in the sense of H ∞ norm. By employing piecewise Lyapunov function and average dwell time techniques, a sufficient condition for the existence of such a filter is exploited in terms of certain linear matrix inequalities. Finally, an example is provided to illustrate the effectiveness of the proposed approach.
Impulsively-controlled systems and reverse dwell time: A linear programming approach
2015
We present a receding horizon algorithm that converges to the exact solution in polynomial time for a class of optimal impulse control problems with uniformly distributed impulse instants and governed by so-called reverse dwell time conditions. The cost has two separate terms, one depending on time and the second monotonically decreasing on the state norm. The obtained results have both theoretical and practical relevance. From a theoretical perspective we prove certain geometrical properties of the discrete set of feasible solutions. From a practical standpoint, such properties reduce the computational burden and speed up the search for the optimum thus making the algorithm suitable for th…
A novel approach to prevent graphene oxide re-aggregation during the melt compounding with polymers
2015
Abstract The technology for the preparation of polymer-GO nanocomposites was investigated by studying the structure-properties relationships of two different systems, based on PA6 and EVA, fabricated by using different preparation methods, i.e. melt mixing, wet phase inversion, and the combination of the two. The morphology of nanocomposites resulted dramatically influenced by the technique adopted and showed to be the critical variable affecting the physical properties of the materials. Finally, the mechanical and dynamic-mechanical of the nanocomposites were improved by using the hybrid technique combining the two procedures.
Network Entropy for the Sequence Analysis of Functional Connectivity Graphs of the Brain
2018
Dynamic representation of functional brain networks involved in the sequence analysis of functional connectivity graphs of the brain (FCGB) gains advances in uncovering evolved interaction mechanisms. However, most of the networks, even the event-related ones, are highly heterogeneous due to spurious interactions, which bring challenges to revealing the change patterns of interactive information in the complex dynamic process. In this paper, we propose a network entropy (NE) method to measure connectivity uncertainty of FCGB sequences to alleviate the spurious interaction problem in dynamic network analysis to realize associations with different events during a complex cognitive task. The p…
A perturbation approach for the response of dynamically modified structural systems
1998
The problem of the structural analysis under changes of dynamical parameters is of particular interest. This is due to the fact that often the real structures are different from the predicted ones. In this paper, an unconditionally stable step-by-step procedure, able to evaluate the deterministic response of linear structures with modifications, is presented. The proposed procedure requires the evaluation of the transition matrix, which is the fundamental operator of the step-by-step solution, by means of a perturbation approach. This technique overcomes the difficulties connected with the evaluation of the eigenproperties of the modified structures usually required to obtain the transition…
Stochastic response determination of structural systems modeled via dependent coordinates: a frequency domain treatment based on generalized modal an…
2019
Generalized independent coordinates are typically utilized within an analytical dynamics framework to model the motion of structural and mechanical engineering systems. Nevertheless, for complex systems, such as multi-body structures, an explicit formulation of the equations of motion by utilizing generalized, independent, coordinates can be a daunting task. In this regard, employing a set of redundant coordinates can facilitate the formulation of the governing dynamics equations. In this setting, however, standard response analysis techniques cannot be applied in a straightforward manner. For instance, defining and determining a transfer function within a frequency domain response analysis…
EGFL7 ligates αvβ3 integrin to enhance vessel formation
2013
Angiogenesis, defined as blood vessel formation from a preexisting vasculature, is governed by multiple signal cascades including integrin receptors, in particular integrin αVβ3. Here we identify the endothelial cell (EC)-secreted factor epidermal growth factor-like protein 7 (EGFL7) as a novel specific ligand of integrin αVβ3, thus providing mechanistic insight into its proangiogenic actions in vitro and in vivo. Specifically, EGFL7 attaches to the extracellular matrix and by its interaction with integrin αVβ3 increases the motility of EC, which allows EC to move on a sticky underground during vessel remodeling. We provide evidence that the deregulation of EGFL7 in zebrafish embryos leads …
First Accurate Normalization of the beta-delayed alpha Decay of N-16 and Implications for the C-12(alpha,gamma)O-16 Astrophysical Reaction Rate
2018
6 pags., 4 figs. -- Open Access funded by Creative Commons Atribution Licence 4.0
Versican and Tumor-Associated Macrophages Promotes Tumor Progression and Metastasis in Canine and Murine Models of Breast Carcinoma
2019
Versican and tumor-associated macrophages (TAMs) are involved in growth and metastases in several cancers. Here, we investigated the potential role of versican, a matrix proteoglycan, and its correlation with TAMs infiltrates in different stages of two different breast cancer models: spontaneous canine mammary gland carcinomas and the murine 4T1 breast cancer model. The stromal versican expression was correlated with TAMs accumulation in tumors with an advanced stage from spontaneous canine mammary carcinoma samples. Versican expression in mice, identified in late stages of tumor progression, was associated to a high number of peri-tumoral infiltrating TAMs. Indeed, TAMs were related to a p…